Field of the Invention
Exemplary embodiments of the present invention relate to an apparatus and method for compressing a video.
Discussion of the Background
Methods of compressing moving pictures (i.e., video) generally aim at increasing a compression rate and improving video quality while maintaining the same bit rate by, in some cases, using a human visual system (HVS). An example of a video compression method is the Moving Pictures Expert Group (MPEG) method. Existing compression methods, such as the MPEG, provide significant decreases in data volume through chroma subsampling by utilizing a human being's reduced insensitivity to color, as opposed to brightness.
Other video compression methods may use foveated video coding. Foveation occurs when a resolution at a point (i.e., fixation point) in an image/video is different than a resolution at other points in the image/video. For example, an average human may only clearly see about 2 degrees around a fixation point and other portions may not be seen clearly. Foveated video coding provides an improved compression rate by estimating the fixation point of a video and impairing portions of the video located remotely from the fixation point. This method takes advantage of the fact that human visual resolution diminishes further from the fixation point.
Blurring is one example of a foveation method. Examples of blurring include filtering, multiresolution & wavelet-related techniques, and sub-band suppression in Discrete Cosine Transform (DCT) domain. Compression methods based on DCT, which is used by most video compression standards, utilize a blur filter in the DCT domain. Blurring techniques are widely used because their compression efficiencies are good.
However, foveation methods have certain limitations because the foveation methods may blur an image/video without affecting and/or adjusting the bit rate. In addition, in some cases, even if foveated video coding is applied to the video, the desired compression effect may not be achieved. For example, when a game character (e.g., fighter 1) is standing close to a rope at the corner of a ring in a game screen, and the fixation point is situated at a face of another character (e.g., fighter 2) in the center of the ring, blurring may be used to compress the video by blurring points in the video away from fighter 2's face; however, the bit rate of the video may is still not be affected.